Dual exhaust

Hey just wondering...

I've heard various contrasting reports on the effects of dual exhausts. Some people say you lose horsepower because you're losing backpressure to the engine, while some people say it is better cause you are increasing exhaust flow.

So which is it?

Depends on your application. Generally, for a 4cyl engine, it loses horsepower. You need a certain amount of back pressure. For 6 cyl's and up, it has it's benefits, increased hp being one of them.

it depends...i think it would be fine only if you got the right sized piping...theirs a conversion chart somewhere that'll show you what to do, i just gotta find it...

what I really meant is that I'd like to see some reports with dyno sheets. If anyone has seen any articles, please point me to them.

cause basically everyone i talk to has different opinions, but no one has facts...

i like facts, not speculation =)

nismoboy, lemme know if you find it, I'd like to see what they say...

well this is what i found, as far as exhaust sizes go when you want to dual an exhaust...

www.isd.net/jhadfiel/exhaustsize.htm

and from what i know, on cars like ours (4 cyl.) theirs probably no real benefits except cosmetically, if you wanna call that a benefit :)

plus a "true" dual exhaust on a 4 cyl. would have a set of 2 exhaust ports to one exhaust and the other 2 remaining exhaust ports to the other exhaust. kinda like this Y Y. from what i've seen on most 4 cyl. cars is that they are more of a dual exhaust outlet, meaning 1 single outlet from the headers, splitting it into 2 outlets,
kinda like a Y...just my thoughts on this
:alien:

I don't see the point to putting a duel exhaust on a 4 cyl other than looking cool. If you went to a mad turbo setup with over 300whp then just get 3" exhaust piping.

As far as performance issues. Depending on your duel piping sizing if it's too big you'll gain top end horsepower but lose low and mid-range torque. If it's smaller you'll gain some low and mid-level torque and lose high end power. Sizing is the key.